i) In making black board chalks.
ii) In surgery for setting fractured bones.
iii) For making casts for statues and toys etc.
iv) In construction industry.

Urea, super phosphate, Ammonium sulphate and potassium nitrate.

water, Sodium hydroxide and coconut oil.

There are two types of rain water harvesting
1. Collecting water from where it falls.
2. Collecting rainwater by constructing bunds.

polar ice - gaps, glaciers and ice sheets in Arctic region and Antarctica.

wells, glaciers, rivers, lakes, ponds, etc.

Magnets lose their properties if they are heated or dropped from a height or hit with a hammer.

(i) Like poles (N-N, S-S) repel each other.
(ii) Unlike poles (N-S, S-N) attract each other.

The main reasons for water scarcity
i) Population explosion
ii) Uneven distribution of rainfall
iii) Decline of ground water table
iv) Pollution of water
v) Careless use of water

Aim: Soap manufacturing.
Requirements:
i) 35 ml of water.
ii) 10 ml of NaOH.
iii) 60 ml of coconut oil.
Procedure:
i) Cover your work area with old newspaper.
ii) Take 35 ml of water in a jar.
iii) Add 10 gram of concentrated NaOH and allow it to cool.
iv) Then add 60 ml of coconut oil drop by drop and stir it well.
v) On getting dried, soap can be obtained.

(i) Direct collection and use of rain water is called rainwater harvesting.
(ii) Excellent and valuable source of water in emergencies.
(iii) Ideal solution for inadequancy of water.
(iv) Increase ground water level.
(v) Reduces rainwater run off and solves drainage problems in houses.

i) Place the iron needle on a table. Now take a bar magnet and place one of its poles near one edge of iron needle and rub from one end to another end without changing the direction of the pole of the magnet. Repeat the process for 30 to 40 times.
ii) Bring a pin or some iron filings near the iron needle to check whether it has become a magnet. Does the iron needle attract the pin / Iron filing? If not continue the same process for some more time.